First-order unbinding and preunbinding in amphiphilic systems

Abstract

We consider swollen lamellar phases in binary systems of amphiphile and solvent. We argue that the abrupt swelling of lamellar phases is the result of a first-order unbinding transition. Employing a self-consistent-field theory to examine a similar system of homopolymer-diblock blends, we demonstrate that the unbinding here is indeed first order by locating the associated line of preunbinding transitions. Along this line, two lamellar phases with different wavelengths coexist.